The INTERNET Database of Periodic Tables

There are hundreds of periodic tables in web space, but there is only one comprehensive database of periodic tables & periodic system formulations. If you know of an interesting periodic table that is missing, please contact the database curator: Dr Mark R Leach.

Since 1993 – and with its rather bland interface – WebElements has given access to vast quantities of in depth chemical data & information. This is the professional chemist's periodic table:

Theo Gray's Photographic Periodic Table is undoubtedly the most attractive PT available in web space, but there is more. Clicking around the website gives access to a host of information, pictures & anecdotes from Theo's extraordinary and extensive collection of chemical elements:

Ptable has a super-slick, and very fast interface. It is data/information rich and is available in 50 languages:

But, it was Mendeleev's Tabelle I that was first near complete periodic table formulation of the then known elements (no Group 18 rare gasses, note). Crucially, Mendeleev identified gaps and was able to make predictions about the chemical properties of the missing substances. Plus, Mendeleev promoted his ideas with great energy:

Werner's 1905 Periodic Table is remarkably modern looking. The formulation is a long form that separates transition metals and rare earths, but he guessed wrong on how many existed:

Janet's Left Step formulation of 1928 is one for the purists as it clearly shows the chemical elements arranged into s, p, d & f-blocks of the recently developed quantum mechanical description of atomic structure:

The long form and medium form PTs have electronegativity trending from top-right (electronegative) to bottom left (electropositive), and many aspects of periodicity corollate with electronegativity: atomic radius, first ionisation energy, etc.

Thus, the long form and medium form periodic tables are commonly used in the classroom:

An Alternative Formulation

The internet database contains many, many alternative formulations, and these are often spiral and/or three dimensional. These exemplified by the 1965Alexander DeskTopper Arrangement. To see the variety of formulations available, check out the Spiral & Helical and 3-Dimensional formulations in the database:

Non-Chemistry PTs

The periodic table as a motif is a useful and commonly used infographic template for arranging many types of object with, from 50 to 150 members.

There are numerous examples in the Non-Chemistry section where dozens of completely random representations can be found: